Why is my Teams site missing channels?

While the contents of the Teams were migrated to the Shared Tenant, each Team had to be recreated in the Shared Tenant due to the adjusted naming standards. The creation of the Team automatically created the “General” channel, however other pre-existing channels were not created. The Team Owner will need to recreate each channel to allow it to resync to the migrated content.

See the following link for instructions: Recreate Teams Channels.